Speed-measuring instrument.



P. EWOLF.

SPEED MEASURING INSTRUMENT.

APPLIUATION FILED APB. 7, 1910.

Patented NOV. 14, 1911.

COLUMBIA PLANOGRAPH Co..wAsH|NGToN, D. c.

FRANZ EMIL WOLF, OF NOWAWES, NEAR POTSDAM, GERMANY.

SPEED-MEASURING INSTRUMENT.

Specification of Letters Patent.

Application iled April 7, 1910. Serial No. 553,916.

To all whom it may concern.'

ing to be a. full, clear, and exact description` of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in speed measuring` instruments, and more particularly to that class of speed measuring instruments in which the centrifugal force of a rotating liquid, such for example as mercury, is used for measuring the speed. 'Ihe centrifugal action can be produced either by means of radially disposed threads of the liquid which are inclosed within a rotating body, or by the rotation of the container of the liquid. In the former case the pressure produced by the centrifugal action is transmitted to the liquid contained within the receptacle, while in the second case the static pressure set up by the revolving rotating liquid within the receptacle is transmitted to the measuring device proper through the inner fbody for which purpose the latter is provided with radial channels. In known speed measuring apparatus of this class, such as areV at present in use, the liquid which is independently movable within the receptacle performs a rotary motion of its own which is different under varying conditions, and which can not be held within definite limits. However, this motion of the liquidand the additional centrifuga-l action produced thereby isa source of errors in the indications of the measuring device, so that the speed measuring instruments in which such additional motion of the liquid takes place are unsuitable for performing exact measurements. v

The object of the improvements is to provide a speed measuringV instrument which is not subject to erroneous indications. And for this purpose, I construct the instrument in such a way, that the yaforesaid injurious rotary motion of the liquid is avoided. In the preferred form I provide one or more partitions within the space provided between the inner body and the wall of the receptacle, which partitions are disposed within the receptacle in a radial or substantially radial position, so as to prevent a motion of the liquid relatively to the receptacle. Thereby the pressure of the liquid caused by the centrifugal action is exactly proportional to the speed of the rotating body, and it can therefore be used for exact measurements.v

For the purpose of explaining the invention several examples embodying the same have been shown in the accompanying drawings in which the same letters of references have been used in all the views to indicate corresponding parts.

In said drawings- Figure l, is a vertical cross-section of a speed measuring instrument embodying the invention, the said measuring instrument comprising a stat-ionary casing and a rotating inner body, Fig. 2, is a horizontal section of the casing of the apparatus illustrated in Fig. l, Fig. 3, is a vertical cross-section showing a modification of the apparatus illustrated in Figs. l and 2, and Fig. 4, is a vertical cross-section of a measuring apparatus comprisin a rotary casing and a stationary inner bo y.

Referring to the example of the measuring apparatus illustrated in Figs. l and 2, a st-ationary casing b is mounted on a suitable bracket a. It is formed with two chambers c and d. The upper chamber c is designed for storing the liquid, and the lower chamber d contains a rotating body e. The latter is secured to a hollow shaft or arbor f, and it is formed wit-h three sect-ions of dierent diameters and each of said sections is formed with radial channels g1, g2, and g3. Within the hollow shaft j a spindle la, is located which is longitudinally shiftable therein and which is formed at its upper end with a longitudinal bore i and with transverse bores 7a, which are adapted to register with the inner ends of either of the channels g1, g2, g3. Within the chamber CZ a partition Z is provided which as nearly as possible extends through the whole area of the free portion of the said chamber, .and which extends closely to the rotating body e. If desired a plurality of suchl partitions may be provided. 'I`o the chamber da perpendicular tube n is secured by means of a tubular stud m, and through the said tube the pressure produced by the centrifugal action is transratented-Nov. 14,1911. l

mitted to the indicating device. The latter by means of a pulley 0 or the like which is secured to the hollow arbor' f. Thereby a centrifugal action is produced within the liquid contained within the radial channels g1, g2, g3, and the said centrifugal action Vproduces a pressure within the chamber Z which is used for measuring the speed of the rotation. The body of the liquid which is inclosed within the chamber (Z and which comes in contact with the outer surface of the rotary body e is liable to be taken alo-ng by friction. But its rotary motion is prevented by the partition Z, so that no motion of its own can be imparted to the said body of liquid. Therefore the pressure within the chamber Z corresponds exactly to the centrifugal action set up within the radial channels of the rotary body c.

By means 0f the shiftable spindle Z1, either one of the channels or sets of channels g1, g2, or g3 are brought into communicatio-n with the chamber c, and the said adjustment can be performed at will. As for the same numbers of revolutions the shorter channels have smaller speeds at their outer ends, and therefore produce lower pressures than the longer channels, by throwing either one of the channels or sets of channels g1, g2, or g3 into communication with the chamber c by the proper adjustment of the spindle ZL the measuring device can be set for different ranges of measurements, that is to say, if the speed is so high, that the longest channels can not be used any more in combination with the measuring device or the scale provided on the same, the spindle ZL is shifted so as to throw a set of shorter channels into communication with the chamber c, and at the same time to throw the set of longest channels out of operation. Thereby the circumferential speed of the end or ends of the indicating channels is varied while the angular speed is not varied. In the same way the apparatus can be adjusted in such a way that the shortest channels are operative.

In the example illustrated in Fig. 3 the arbor f which carries the rotary body c projects upward from the said body and through the chamber c. The chamber Z is provided with two partitions Z, Z which embrace the rotary body e and prevent the liquid from being taken along by friction. The rotary body e is constructed in the form of a disk and it is provided with two radial bores gL and g5 which are disposed within the same plane. The spindle f is rotatable within the disk c and it is formed with an inner bore z" which communicates at its upper end with the chamber c', and which with its lower end can be thrown into communication with the channel g4 or g5 by rotating` the spindle f. The operation of the apparatus is the same as that described with reference to Figs. 1 and 2, rotation of the liquid within the chamber d being prevented by the partitions Z, Z.. By means o-f the channels g4 and g5 different ranges of measurements are possible.

In the example illustrated in Fig. 4, a stationary inner body is provided which by means of a stationary hollow shaft ,f2 is supported on a bracket a2. It is provided with a plurality of channels gG and g7 the mouths of which are at different distances from the perpendicular axis of the disk.`

.amples illustrated in Figs. 1 to 3 the partitions Z and Z have the function to prevent rotation of the body of the liquid inclosed within the casing Z). In the example shown in Fig. 4L similar partitions Z2 are provided which, however, have the function to takeV the liquid along upon rotation of the casing Z22. Therefore, by the said partitions I am enabled to prevent the liquid from being retarded by its friction on the outer face of the stationary inner body e2, which retardation would cause erroneous indications of the instrument.

By reason of the partitions Z2 the liquid inclosed within the pressure chamber Z2 is always carried along at the speed of the casing b2, and the pressure produced within the said chamber' by centrifugal action is transmitted through either one of the channels g or g7 and the bore of the spindle L2 to a measuring device, such for example as a manometer. As the static pressure is in direct proportion to the speed of the revolution of the liquid, it decreases toward the axis of the instrument. Therefore, by means of the channels g and g7 of different radial lengths different ranges are provided for the measurements.

In order to prevent the liquid contained within the upper chamber c2 from taking part in the rotation of the casing b2'and thereby to adjust its surface along a paraboloid, I prefer to provide partitions r which are secured to the stationary shaft f2. The chambers c and 02, Figs. 3 and 4C, respectively, serve as storage chambers and the iiuid mass in them acts as a buffer to take up shocks due to sudden changes of speed and other causes. Thereby the construction of the instrument is particularly simple, and its operat-ion is very easy, so that it can be operated at a minimum of energy.

I claim herein as my invention:

1. In a rotary speed measuring instrument the combination vvith a casing, and an armless body inclosed by said casing and having a substantially radial bore communicating externally With the inside of the casing, said casing and body having a relative rotary movement and inclosing a liquid, of means to counteract friction between the inner body and the liquid inclosed Within the casing, and means to measure t-he pressure produced by centrifugal action Within said liquid.

2. In a rotary speed measuring instrument the combination With a casing, and an armless body inclosed by said casing and having a substantially radial bore communicating externally With the inside of the easing, said casing and body having a relative rotary movement and inclosing a liquid, of a partition disposed Within said casing between the inner Wall of the same and the outer surface of said body, and means to measure the pressure produced by centrifugal action Within said liquid.

3. In a rotary speed measuring instrument the combination with a casing, and a body inclosed by said casing and having substantially radial bores communicating externally with the inside of the casing at different distances from the axis of the instrument, said casing and body having a relative rotary movement and inclosing a liquid, of means to measure the pressure produced by centrifugal action Within said liquid at either one. of the outer ends of said radial bores.

t. In a rotary speed measuring instrument, the combination with a casing, a body inclosed by said casing and having a plurality of substantially radial bores communicating externally with the inside of the casing at dierent distances from the axis of the instrument, said casing and body having a relative rotary movement and inclosing a liquid, of a spindle adapted to close all but one of the bores at their inner ends, and means to measure the pressure produced at the outer end of the open bore.

In testimony whereof I afix my signature, in presence of tivo Witnesses.

FRANZ EMIL VOLI Vitnesses HENRY IIAsPnR, VOLDEMAR HAUPT.

Copies 0f this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

